iMac 2012 boot from USB3 with SSD?

Im considering to buy a new iMac base model ( 8GB RAM, 1TB 5400RPM HDD) and want to explore an option of booting this one form the external USB3 port with SSD. Considering USB3 speeds are similar to SATA3 I think I would be able to achieve the same level of speeds as if I have internal SSD. The plan is to stick enclosure on the back of the iMac on some 3M tape.

What I have:

60Gb Mushkin SATA2 SSD

External USB3 enclosure for 2.5 inch disk

Questions / Concerns I have regarding the setup:

Is 60Gb going to be enough for Mountain Lion and some apps? (I do use it now for Windows 7 + Apps and still have 15GB fee, so not a heave apps user).

Would I be able to install ML on external USB3 disk without going to Apple Store? (does apple keep OS image on some hidden partition for reinstall?)

Would I be able to boot from USB3 port? Maybe someone who currently have latest Ivy Bridge MacBook or Air can confirm and did tried this before?

Would I be able to configure iMac to persistently boot from external disk or will I need to select it every boot time?

Will sleep/wake function work with OS on external USB disk?

Another option is probably to boot from external Thunderbolt but I believe it will be more expensive than buying SSD option from Apple.

Sorry if above questions are dumb, but its my first experience with Apple hardware, beside iPhones and iPads for last 4 years.

I dunno USB 3 is quite a bit slower than thunder port. Im looking at the laCie rugged SSD 120 GB for $200, the 256 gb is $350. But has thunderport and USB 3 so would make a awesome external OS drive. Plus you dont have to tear your iMac apart you keep warranty and this thing can take one heck of a beating if your like me and travel a lot.

Im considering to buy a new iMac base model ( 8GB RAM, 1TB 5400RPM HDD) and want to explore an option of booting this one form the external USB3 port with SSD. Considering USB3 speeds are similar to SATA3 I think I would be able to achieve the same level of speeds as if I have internal SSD. The plan is to stick enclosure on the back of the iMac on some 3M tape.

What I have:

60Gb Mushkin SATA2 SSD

External USB3 enclosure for 2.5 inch disk

Questions / Concerns I have regarding the setup:

Is 60Gb going to be enough for Mountain Lion and some apps? (I do use it now for Windows 7 + Apps and still have 15GB fee, so not a heave apps user).

Would I be able to install ML on external USB3 disk without going to Apple Store? (does apple keep OS image on some hidden partition for reinstall?)

Would I be able to boot from USB3 port? Maybe someone who currently have latest Ivy Bridge MacBook or Air can confirm and did tried this before?

Would I be able to configure iMac to persistently boot from external disk or will I need to select it every boot time?

Will sleep/wake function work with OS on external USB disk?

Another option is probably to boot from external Thunderbolt but I believe it will be more expensive than buying SSD option from Apple.

Sorry if above questions are dumb, but its my first experience with Apple hardware, beside iPhones and iPads for last 4 years.

Thanks!

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I bought the seagate thunderbolt adapter in preparation of getting a new imac back in the summer. I currently have a 2011 mini that I tested it with. Hooked up the ssd to it, used carbon copy clone and cloned, then rebooted the mini holding R or whatever to choose boot disk, booted off the thunderbolt mounted drive, did speed tests. Very very quick, I think it was 95% of what I get with the same drive (yes I have 2) as I get internally mounted. I am so impressed that even with the 2012 having a better choice for ssd on the new imac I am still going to just get the 1tb model and use my own external ssd for use and the internal 1tb will be my time machine backup

I bought the seagate thunderbolt adapter in preparation of getting a new imac back in the summer. I currently have a 2011 mini that I tested it with. Hooked up the ssd to it, used carbon copy clone and cloned, then rebooted the mini holding R or whatever to choose boot disk, booted off the thunderbolt mounted drive, did speed tests. Very very quick, I think it was 95% of what I get with the same drive (yes I have 2) as I get internally mounted. I am so impressed that even with the 2012 having a better choice for ssd on the new imac I am still going to just get the 1tb model and use my own external ssd for use and the internal 1tb will be my time machine backup

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I was checking out that sea gate adapter did you get the base one where it is like a stand? Or the one that lays flat. Saw since it uses a sata connection you can use any ssd or Hdd to it!! But wondering if the smaller one $99 can do a 3.5 Hdd ? If so that would be a sweet option. Plus when internal ssd prices drop u can just plug one in with no jack up in price for a housing. Very tempting hmmmmm

- 2012 iMac for aud $1450 and use external usb3 case with 60gb ssd. Trade off is slower system disk.

Starting to think that option 1 is better. Speed of system is mode dependent on underlying disk subsystem and I probably will to notice difference in CPU. There is also a little chance that In the future there will be thunderbolt to usb3 adapters that can be used with second thunderbolt port available on 2011 iMac.

Can someone tell me if sleep mode works ok with OS on external thunderbolt disk?

I was checking out that sea gate adapter did you get the base one where it is like a stand? Or the one that lays flat. Saw since it uses a sata connection you can use any ssd or Hdd to it!! But wondering if the smaller one $99 can do a 3.5 Hdd ? If so that would be a sweet option. Plus when internal ssd prices drop u can just plug one in with no jack up in price for a housing. Very tempting hmmmmm

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The portable one is bus powered, so it is doubtful that a full size 3.5" HD would work well on that. The base stand is self powered and would be the choice for a 3.5" drive. I don't recall offhand if the base stand has dual TB ports, but that would be a big advantage if you expand the TB externals.

I also thinking of a USB 3 external SSD for the iMac.
Look at this thread, it is possible to get really good spedds with the right case. It is important that the case support SATA 3, most of the case only have SATA 2.http://forums.macrumors.com/showthread.php?t=1483374

I also thinking of a USB 3 external SSD for the iMac.
Look at this thread, it is possible to get really good spedds with the right case. It is important that the case support SATA 3, most of the case only have SATA 2.http://forums.macrumors.com/showthread.php?t=1483374

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With usb3, you will maintain better throughput if you limit the usb devices. The more you have the lower the throughput.

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